A electronic smoking device, such as an electronic cigarette (e-cig or e-cigarette), electronic cigar, personal vaporizer (PV) or electronic nicotine delivery system (ENDS) is a battery-powered vaporizer which creates an aerosol or vapor. In general, these devices have a heating element that atomizes a liquid solution known as e-liquid.
E-liquid refers to a liquid solution that when heated by an atomizer produces aerosol. The main ingredients of e-liquids are usually a mix of propylene glycol (PG), glycerin (G), and/or polyethylene glycol 400 (PEG400), sometimes with differing levels of alcohol mixed with concentrated or extracted flavorings. Optionally, nicotine may be included. E-liquid is often sold in bottles or pre-filled disposable cartridges. Pre-made e-liquids are manufactured with various tobacco, fruit, and other flavors, as well as with different concentrations of nicotine.
As shown in FIG. 6, in some electronic smoking devices, E-liquid is heated at an atomizer to produce aerosol when the device senses a puff action of a user. The aerosol typically is entrained in air flow through a passageway 12 in the device to a mouthpiece or outlet. The passageway may be aligned on a longitudinal center of the electronic smoking device or along the perimeter of the electronic smoking device.
It is desirable to monitor the amount of the aerosol generated in real-time for the purposes of for example, controlling the amount of aerosol generated during each puff, and estimating the remaining amount of the E-liquid in the E-liquid cartridge or E-liquid container